A carbon dioxide-rich fluid contains at least 30 mol % of carbon dioxide or at least 60 mol % of carbon dioxide or even at least at least 80 mol % of carbon dioxide, or even at least 95 mol % of carbon dioxide.
In order to reduce the CO2 emissions of human origin to the atmosphere, methods have been developed for capturing the CO2 generated in a given process. They involve extracting the CO2 from a gas generated by the process, optionally purifying it, and lastly, in general, compressing it for its transportation within a pipeline system.
It should be stated at this point that another route for transporting the CO2 is to liquefy it and load it onto boats designed for such use. Some CO2 liquefaction cycles entail the compression of the CO2 to a pressure such that it can be condensed to a temperature close to ambient. The liquid is subsequently depressurized to the transport pressure (typically between 6 and 10 bar a). The invention will then be applicable to this type of factory.
It should also be stated that despite major differences between the CO2 capture methods (post-combustion, mention may be made of washing with amines or with aqueous ammonia; there is also gasification of the fuel, chemical loop processes, ferrous metallurgical processes, cement plants, or any industrial process that uses air), they virtually all include compression of the relatively pure CO2, and are therefore suitable for implementing the invention described hereinafter.
The pressures at which the CO2 is supplied to the pipeline systems are generally greater than 150 bar abs. In the state of the art, the CO2 is compressed to the final pressure in a centrifuge compressor (given the flow rates in question in the applications of CO2 capture in factories).